Magnetic resonance imaging (MRI) evaluation of pathologic complete response (pCR) in different breast cancer subtypes after neoadjuvant chemotherapy (NAC).

1111 Background: MRI is being used to address treatment response to NAC in breast cancer patients. However, its ability to predict pCR in histologically different tumors remains unclear. We tried to investigate the usefulness of MRI in evaluation of pCR in different breast cancer subtypes after treatment with NAC. Methods: Serial MRI studies were acquired before, during and after NAC in 75 evaluable patients. MRI interpretation included lesion size, morphology and dynamic enhanced evaluation imaging with initial and late enhancement. On the basis of the final MRI, response was determined to be a clinically complete response (CCR) when no residual tumor and no late enhancement were found. By using inmunohistochemistry and fluorescence in situ hybridization (FISH) for human epidermal growth factor receptor 2 (HER2/neu) amplification, tumors were divided into three subtypes: triple negative, HER2 positive, and estrogen receptor (ER) positive/HER2 negative. Every patient received chemotherapy with taxanes and...